Wheel made of fiber composites and process for the manufacture thereof

ABSTRACT

A one-part wheel which is made of fiber composites without interruption of fibers with excellent mechanical properties and with low weight at the same time as well as a process for the manufacture thereof. The wheel has especially a rim well as well as a wheel disk passing over into a wheel flange of the rim well, where the wheel disk is formed at least partly by fiber layers, which run from the rim well over a wheel flange and the wheel disk. The wheel is manufactured by a multipart mold with parts displaceable at least in the axial direction. The mold is completely removed after the deposition of fibers or remains as a lost core in the wheel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional under 37 CFR 1.53(b) of pending priorapplication Ser. No. 14/363,113 filed Jun. 5, 2014, which is a UnitedStates National Phase Application of International ApplicationPCT/EP2012/074183 and claims the benefit of priority under 35 U.S.C.§119 of German Patent Application DE 10 2011 087 936.6 filed Dec. 7,2011, the entire contents of each application are incorporated herein byreference.

FIELD OF THE INVENTION

The invention pertains to a one-part wheel made of fiber compositeswithout interruption of fibers as well as a process for the manufacturethereof.

BACKGROUND OF THE INVENTION

The use of lightweight materials in the manufacture of vehicles,especially in the manufacture of spare parts and performance parts, isknown from the state of the art. The use of light metals, such asaluminum and magnesium, for body parts and small parts has becomegenerally accepted not only in racing or for small series, but alsomeanwhile in products for the mass public. In addition, because of theirexcellent ratio of weight to mechanical properties, fiber compositeshave lately been gaining increasing significance.

So that a component made of fiber-reinforced plastic can optimallyabsorb multiple stresses acting on it, it should also containreinforcing fibers with multiple orientations, since they can absorbthese forces, especially lengthwise. In addition, components made offiber-reinforced plastic, which consist of continuous fiber layers,which ideally pass through the entire component, have proven to besuccessful.

In components which have complicated shapes and are highly stressed,such as, e.g., wheels, these requirements on the inner structure offiber-reinforced components were usually not met up to now. This is theresult of the fact that no process for the manufacture of a wheel, whichcan deposit continuous fibers corresponding to the geometry of a wheel,is known from the state of the art.

Therefore, in the state of the art, particularly processes for themanufacture of wheels are found in injection molding, wherein only veryshort reinforcing fibers are used in favor of the formability of thecomponents. Another possibility is for the wheels to have a multipartdesign, whereby the simple geometry of the individual parts permits theconstruction thereof from long-fiber-reinforced plastics.

A vehicle wheel made of fiber-reinforced plastic as well as a processfor the manufacture thereof is described in U.S. Pat. No. 3,917,352 A.In this case, the wheel has a one-part design and comprises both a rimwell and a wheel disk. The wheel is manufactured by winding a fabrictube around the two halves of a mold, whereby the wheel disk can beformed by means of winding around a groove. Deposition of fibers duringthe winding does not, however, take place sufficiently in apositive-locking manner; hence, the fabric tube must be additionallywound around with fabric tape or filaments. A forming of the wheel diskalready during the deposition of the fiber layers is not disclosed.

The subject of DE 42 23 290 B4 is a composite synthetic resin wheel,which consists of a plurality of partial cast parts and its wheel diskpasses directly over into one of the wheel flanges. The partial castparts have a corresponding threaded section on their connectingsurfaces, such that they can be joined together by means of a screwconnection. Each of the individual partial cast parts consists ofshort-fiber-reinforced plastic, as a result of which the construction ofsuch a rim from continuous fibers without interruption of fibersaccording to the disclosure of this publication is not possible. Becauseof the structure of the composite synthetic resin wheel, mechanical weakpoints must be taken into account especially at the connecting points ofthe partial cast parts.

DE 100 06 400 A1 discloses a disk wheel consisting of fiber-reinforcedplastic at least in sections as well as a process for the manufacturethereof. In this case, the disk wheel preferably consists of a metallicrim well as well as a rim well consisting at least partly ofunidirectional fiber SMC (sheet molding compound). The wheel disk andrim well are connected with one another in substance or in apositive-locking manner or by means of fastening means having adifferent action. In the preferred case of positive locking, the wheeldisk has a plurality of pin-like projections that correspond with aplurality of holes in the rim well. Such fastening means can beconstructed with fiber reinforcement only with great difficulty andhence frequently have low fiber volume percentages. Hence, reducedmechanical properties of the disclosed disk wheel compared to componentsconstructed from fiber composites in one part had to have been assumed.Such a one-part design of a disk wheel is not described in thepublication.

U.S. Pat. No. 4,721,342 A discloses a fiber-reinforced plastic wheelwith an essentially three-part design. In particular, the wheel disk,consisting of fiber material, of the wheel is constructed separately andis connected in substance to the inner two hollow-cylinder-like layersof fiber material. By means of connecting the two hollow-cylinder-likefiber layers and the fiber layer forming the wheel disk first in theconsolidation process, an expensive fixing of the fiber layers to oneanother is guaranteed during the deposition of fibers. Furthermore,reduced mechanical properties at the connection points of the individualparts compared to the rest of the component must be assumed.

An essentially two-part fiber-reinforced vehicle wheel made of compositeis disclosed in US 2005/0104441 A1. The vehicle wheel consists of afiber-reinforced rim well as well as a fiber-reinforced wheel disk,which are connected with one another in substance and in apositive-locking manner wherever possible first in the consolidationprocess. Thus, there is also no fiber reinforcement of the rim in thedisclosed wheel precisely in the especially stressed area of thetransition from the wheel disk to the rim well. According to thepublication, the preforms for the rim well and the wheel disk are alwaysprepared isolated from one another; thus, a vehicle wheel with aone-part design without interruption of fibers is not disclosed in thispublication.

A light metal wheel, in which the wheel disk passes over into the outerwheel flange, is disclosed in DE 10 2004 028 841 A1 and in DE 103 02997A1. Furthermore, the wheel may have a cavity in the undercut area of theouter wheel flange, as a result of which an especially good stabilityshould be obtained. The design of such a wheel made of fiber compositeis not disclosed in the publication.

SUMMARY OF THE INVENTION

An object of the present invention is to overcome the drawbacks of thestate of the art and provide a wheel made of fiber composite, which hasexcellent mechanical properties with low weight at the same time, andwhich is simple and cost-effective to manufacture.

The object of the present invention is accomplished by the features ofthe present invention.

The wheel according to the present invention advantageously has a shape,which corresponds to the greatest extent to the shape of usual wheels ofmotor vehicles. For the mounting of tires, the wheel has a rim well,which is defined by wheel flanges on both sides. Corresponding to theorientation of the rim in the state mounted on the motor vehicle, adistinction is made between the outer wheel flange on the side facingaway from the vehicle and the inner wheel flange on the side facing thevehicle. Since double tires of utility vehicles are, however, frequentlyformed from wheels, whose wheel disks are facing each other, thedesignation of first and second wheel flanges is used below as analternative. Between the wheel flanges, the rim well has a well, inwhose area the wheel has a smaller circumference than at the wheelflanges. The center between the wheel flanges is designated as the rimcenter. The well itself may have other designs, e.g., a hump or rimshoulder, which are of secondary importance for the present invention,however.

The wheel according to the present invention advantageously has a shape,which corresponds to the greatest extent to the shape of usual wheels ofmotor vehicles. For the mounting of tires, the wheel has a rim well,which is defined by wheel flanges on both sides. Corresponding to theorientation of the rim in the state mounted on the motor vehicle, adistinction is made between the outer wheel flange on the side facingaway from the vehicle and the inner wheel flange on the side facing thevehicle. Since double tires of utility vehicles are, however, frequentlyformed from wheels, whose wheel disks are facing each other, thedesignation of first and second wheel flanges is used below as analternative. Between the wheel flanges, the rim well has a well, inwhose area the wheel has a smaller circumference than at the wheelflanges. The center between the wheel flanges is designated as the rimcenter. The well itself may have other designs, e.g., a hump or rimshoulder, which are of secondary importance for the present invention,however.

In addition, the wheel according to the present invention has a wheeldisk, which is used to connect the wheel to the wheel hub or to thewheel suspension. As an alternative, the wheel disk may also be formedonly by means of a flange, to which it is fastened especially in apositive-locking manner by means of bolt connections or even by means ofa toothed integration of an inner wheel disk element (which may also beformed by means of a wheel spider or wheel rim, among other things). Inthis case, the inner wheel disk or wheel spider would then establish theconnection to the wheel hub or wheel suspension. Accordingly, the wheeldisk represents a connecting surface, which extends radially from theaxle or wheel hub, to the hollow-cylinder-like rim well, at which it ispositioned at an angle. This may be a right, acute or obtuse angle. Inaddition, the wheel disk may have a contoured shape, both for aestheticand for functional reasons, especially an increase in strength.

Furthermore, the wheel disk is preferably designed as a wheel spider,whereby the radially extended connecting surface has openings, e.g., sothat a defined number of spokes represent the connections between thewheel hub and the rim well.

In the wheel according to the present invention, the wheel disk passesover into a wheel flange, as a result of which the hollow cylinderformed by the rim well has a one-sided top surface. The wheel disk ispositioned at the axially outermost point of the rim well, the wheelflange, and from there runs radially inwards in the direction of theaxis of rotation of the rim well or wheel.

According to the present invention, the wheel is made of fibercomposite, which has reinforcing fibers embedded in duro- orthermoplastic matrix material. Carbon, fiberglass or aramid fibers arepreferably used as reinforcing fibers.

The wheel, i.e., the wheel disk and rim well, has a one-part design madeof fiber composite. In this case, the reinforcing fibers are preferablyarranged as continuous fibers in the form of layers in fiber layers inthe wheel disk and the rim well, and at least some of the number offibers run between the wheel disk and the rim well without interruption.Since the fiber layers are preferably formed from continuous fibers, thefiber layers pass over into one another at reversal points, whereby areversal of direction of at least some of the fibers takes place. Thereversal points are preferably located on the periphery of the one-partrim, i.e., on the one hand, on the wheel flange, and, on the other hand,on the inner limitation of the wheel disk, which is the so-called wheelhub hole. Advantageously, the fiber layers have an increased stabilityat these reversal points in the consolidated state, as a result of whicha special strength of the wheel at the especially stressed areas, forexample, the wheel connection and wheel flanges, is advantageouslyachieved.

For the purpose of a local reinforcement, reversals and thus connectedpassages of the fiber layers into one another may also be provided inother areas of the rim or of the wheel disk.

Thus, the fiber layers preferably run at least partly withoutinterruption from the rim well, over one, especially the outer, wheelflange into the wheel disk. The term “partly” describes here that notall fiber layers, but rather at least one such fiber layer runs. Theremay also be fiber layers that run only in the rim well or only in thewheel disk.

Depending on the manufacturing process, the fiber layers may consist ofbraiding, fabric, mesh, or scrim. Especially preferably, the fiberlayers are made of braided continuous fibers.

In addition, in the manufacture of a wheel disk formed as a wheelspider, one or more layers may be deposited only on parts of thecircumference of the wheel. These fiber layers, which are depositedincompletely in various areas along the circumference, form separate,arc-like connections between the rim well and the wheel hub. These fiberlayers are especially preferably textile patches or scrim.

Since the fiber layers, preferably at least some of their number, runwithout interruption between the rim well and wheel disk, these alsohave a change in their extension or orientation in the area of the wheelflange, to which the wheel disk is connected. The fiber layers areoriented in a rotationally symmetric pattern about the axis of rotationdefined by the wheel hub in the area of the rim well as an outer radiallimitation or jacket surface of a hollow cylinder. They preferably forma plurality of layers arranged radially one on top of the other. Thefiber layers are essentially arranged one on top of the other in theaxial direction in the area of the wheel disk. Essentially here meansthat bulges, structurings or slopes up to 15° from the plane, in whichthe connecting wheel flange lies, may occur for reasons of opticaldesign or improved absorption of forces. To make possible the differentorientation of the fiber layers in the rim well and the wheel disk, atleast some of the fiber layers are bent over radially inwards in thearea of the connecting wheel flange.

Due to the construction of the rim well and wheel disk from at leastpartly shared continuous fibers, a wheel with a wheel disk connectedwith high strength, in which the forces and torques acting on the wheeldisk are optimally transmitted to the rim well, is thus advantageouslyformed. Thus, the wheel has a higher stability compared to a multipartrim design especially in the connection area of the wheel disk to therim well. Since the fibers according to the present invention are bentover radially inwards at the axially outermost point of the rim well,the change in orientation of the fiber layers takes place in the area ofthe wheel flange. In order to fulfill its function, which is the lateralstabilization of the tire on the rim well, this wheel flange has agreater radial extension than the rim well. In order to achieve thischange in circumference, the fiber layers of the rim well are orientedpreferably in an almost radial direction outwards at the axially inwardsdirected flank of this wheel flange. Due to the bending over of thefiber layers radially inwards in the area of the wheel disk, a reversalof the orientation of the fibers also takes place at this wheel flange,but without fiber layers deposited on one another passing over into oneanother. Advantageously, the fiber layers also have an increasedstability at this reversal point in the consolidated state, as a resultof which an increased strength is also achieved at the highly stressedwheel flange.

Furthermore, the design of the fiber layers bent over radially inwardsas a flange for fastening to the inner wheel disk or to a wheel rim ispreferred. For this, the fiber layers bent over radially inwards have ashorter extension in the radial direction than in the design of acomplete wheel disk. Thus, the fiber layers form an edge orientedpredominantly radially inwards, which is positioned at the wheel flange.Especially preferably, the flange has means for fastening the wheel diskor the wheel spider. These means are either integrated in the flangealready during the manufacturing process or inserted after theconsolidation of the rim, e.g., through a hole.

The fiber layers bent over radially inwards are preferably arranged,such that the wheel disk formed from them is present eithercircumferentially, i.e., as a full disk in the proper sense, or in theform of individual circular disk segments, i.e., as a wheel spider. Inthe case of the individual circular disk segments, these are especiallypreferably formed differently, both as concerns their width and theirradial extension.

In the design of the fiber layers bent over (radially) inwards as awheel spider in the form of arc-like connections between the rim welland the wheel hub or wheel suspension, the fiber layers have, in theradially inwards extended plane of the wheel disk, openings, whichextend in the radial direction maximally from the wheel flange to thewheel hub or the wheel suspension. In addition, the openings may haveany dimensions vertically to the radial direction as long as asufficiently stable connection between the rim well and the wheel hub isstill formed by the fiber layers bent over radially inwards.

The orientation of the continuous fibers within the individual fiberlayers may vary between different fiber layers. Preferably, thecontinuous fibers in the fiber layers in the area of the rim well have adifferent angle in relation to the axial direction of the wheel than thecontinuous fibers in the area of the wheel disk in relation to theradial direction of the wheel. Here, the orientation of the fibers inthe rim well is, above all, determined by the desired mechanicalproperties of the rim well. The orientation of the continuous fibers inthe area of the fiber layers bent over radially inwards is used forpreparing a high-strength wheel disk with an optimal transmission offorces to the rim well.

The continuous fibers of the fiber layers in the area of the rim wellhave a fiber angle of 0° to ±90°, preferably ±3° to ±87° and morepreferably ±30° to ±70° in relation to the axial direction of the rim.When using suitable textile semifinished products, e.g., unidirectionaltubes or braiding with filler yarn (with a fiber angle 0° in relation tothe axial direction of the wheel), the angles of the continuous fibersin relation to the axial direction of the wheel may advantageously be±0° to ±90°. A variation of the angle of the continuous fibers indifferent fiber layers of the rim well is especially preferable, since abetter resistance to changing stresses is thus advantageously achieved.Thus, the fiber layers, whose fibers are oriented almost parallel to theaxial direction of the wheel, can absorb impact stresses actinglaterally on the wheel flanges, in particular. Fiber layers, whosecontinuous fibers are oriented almost vertically to the axial directionof the wheel, may advantageously absorb torsional forces occurringduring acceleration or braking processes.

The continuous fibers of the fiber layers in the area of the wheel diskhave a fiber angle of ±3° to ±87°, preferably ±10° to ±80°, morepreferably ±20° to ±75° and more preferably ±30° to ±70° in relation tothe radial direction of the wheel. When using textile semifinishedproducts, the angles of the continuous fibers relative to the radialdirection of the rim may also be from ±0° to ±90°. The transmission oftorques from the hub to the tire stresses the wheels less than theimpact stresses that occur during the driving through potholes orunevennesses. Due to an alignment of fibers almost in the radialdirection of the wheel, these pulse-like stresses may be transmittedespecially well via the wheel disk to the hub or wheel suspension. Aneven better stability of the wheel is preferably achieved by the fibersof different fiber layers having different orientations from oneanother.

Furthermore, the running of the fibers in the individual layers of therim well according to the present invention is preferably adaptedcorresponding to the mechanical stresses to be expected. The adaptationhere takes place primarily by setting the orientation of the fibers, byadapting the layer thickness as well as optionally by inserting anadditional textile inlay between the fibers layers at especiallystressed points according to expectations. Furthermore, a reinforcedfiber deposition in certain areas of the rim well or of the wheel diskcan take place due to the setting of the position of the reversal pointsof the fiber deposition.

The wheel disk of the wheel according to the present invention has asection for fastening the wheel to the wheel hub in an especiallypreferred embodiment. This section may be characterized by a specialorientation of fiber layers in relation to the radial direction of thewheel, e.g., in a centering surface. Furthermore, the section maycontain fastening means, e.g., bolt holes or a central closure.

Furthermore, the wheel according to the present invention preferably hasat least a completely or partly circumferential cavity in the axial areabetween the wheel flange connecting to the wheel disk and the rim well,especially the well, or in the undercut area of the wheel flangeconnecting to the wheel disk. This cavity is preferably entirely definedby fiber layers, whereby especially preferably the axially outerlimitation of the cavity is formed by the wheel disk, the radially innerlimitation of the cavity passes over into the rim well, especially thewell, and the radially outer limitation of the cavity is formed by theprofile of the rim well from the wheel flange in the direction towardsthe rim center, and in particular, up to the well. If the cavity is onlypartly circumferential, then additional limitations are located betweenthe individual cavities. Such a design of the cavity advantageouslyleads to an increase in strength in the area of the hollow profile andlow remaining weight at the same time. Furthermore, the fiber layerdefining the cavity radially inside represents an additional connectionof the rim wheel and the wheel disk. Since the continuous fibers here donot experience an almost full reversal of direction, this connectionleads advantageously to a better transmission of forces between thewheel disk and the rim well.

Furthermore, at least one entirely or partly circumferential lost coreis preferably integrated in the undercut area of the wheel flangeconnecting to the wheel disk. Like the cavity already described, thislost core may be defined entirely or else only partly by fibers layers.If the at least one lost core is partly defined by fiber layers, theaxially outer limitation of the cavity is formed by means of the wheeldisk and the radially outer limitation of the cavity is formed by meansof the profile of the rim well from the wheel flange connecting to thewheel disk in the direction of the rim center, and especially up to thewell. The adhesion of the lost core is then achieved by means of apositive-locking connection or by means of connection in substance,e.g., by means of using an adhesive or by means of consolidation. If anonly partly circumferential core is integrated, additional limitationsmay be located between the individual core segments. The lost corepreferably consists of plastic, foamed plastic or metallic materials.Due to the integration of a lost core, the strength of the rim isadvantageously increased in the area of the wheel flange connecting tothe wheel disk. In the design of the fiber layers bent over radiallyinwards as a flange, means for fastening the wheel disk or the wheelspider are preferably integrated in the core.

Furthermore, the subject of the present invention is a process for themanufacture of a wheel made of fiber composite.

According to the present invention, a multipart core mold is used here.This multipart core mold comprises a cylinder-like rim well core, whoseradial limiting surface corresponds to the contour of the rim well ofthe rim to be manufactured. In addition, an axial limiting surface ofthe rim well core corresponds to the contour of the wheel disk of thewheel to be manufactured. An auxiliary core, which is displaceable inthe axial direction, especially along the rotation symmetry axis of thecore mold, and approximately ends with the rim well core in the radialdirection, which auxiliary core is detachably connected with the rimwell core, is connected to the rim well core at this axial limitingsurface.

At least one layer of fiber material is deposited on this core mold,such that the fibers are deposited in a positive-locking manner on thecircumference of the core mold and in the axial direction on the rimwell core and the auxiliary core. Consequently, the radial limitingsurface of the core mold is surrounded by fiber material in a tube-likemanner. The fiber material is deposited on the core mold in the processaccording to the present invention by means of draping multiaxial scrim,scrim cuts or fabric layers on the core mold, by winding around the coremold with tape braid or flat-pressed round braid and/or by braiding thecore mold with braided filament.

After the deposition of the fibers on the multipart core mold, theauxiliary core is removed from the rim well core, and in particulardisplaced in the axial direction facing away from the rim well core,whereby this movement of the auxiliary core takes place until this iscompletely extracted from the fiber material deposited in a tube-likemanner on the auxiliary core. Consequently, an end of the tube-shapedfiber material, projecting over the rim well core, is formed.

In a next process step, the fiber material deposited beforehand on theauxiliary core is bent over in the radial direction inwards and isformed in one piece with the axial limiting surface of the rim wellcore. Consequently, the positive-locking deposition of continuous fiberstakes place, which also lie in a positive-locking manner on the radiallimiting surface of the rim well core, on its face, imaging the contourof the wheel disk. Thus, a fiber preform made of continuous fibers,which is formed in one piece with the rim well core in apositive-locking manner, which has the contour of the rim to bemanufactured, comprising the rim well and the wheel disk, is created.

In a likewise preferred embodiment of the process, the fiber material isdeposited only in the area of the rim well core along its entirecircumference. On the other hand, in the area of the auxiliary core,fiber layers are deposited incompletely along the circumference of therim well core. By means of bending over these incompletely depositedfiber layers radially inwards, a wheel disk designed as a wheel spideris produced. Textile patches or scrim are preferably used in theincomplete deposition of fiber layers along the circumference of the rimwell core.

For the manufacture of the actual wheel made of fiber composite, thefiber preform deposited on the rim well core is inserted into amultipart, preferably metallic outer mold. Once the preform has beeninserted, the outer mold is closed, and the fiber material isconsolidated with duro- or thermoplastic matrix material. In this case,the matrix material is preferably injected into the mold with a definedpressure and a defined temperature. In the mold, the fiber composite isconsolidated by binding the matrix material and fiber preform,preferably under defined pressure-temperature conditions, during adefined period. After the curing of the matrix material, the finishedwheel, comprising the rim well and wheel disk formed in one piecetherewith, is removed from the outer mold. The parameters of pressureand temperature actually to be used in the consolidation depend on thematerials used. Since these materials are from the state of the art,these parameters are known to the person skilled in the art.

In a preferred embodiment, a thermo- or duroplastic binder is added tothe fibers during deposition of the fibers. This may take place, forexample, in the powder form, but also by using impregnated fibers. Afterthe fiber deposition, the fiber preform is subsequentlypre-consolidated. In the preferred use of thermoplastic binders, thiscan be carried out, for example, in a technologically simple andcost-effective manner with a hot air blower. After pre-consolidation,the core mold may then be removed from the fiber preform. At a laterpoint in time, the fiber preform is then inserted into the consolidationmold and the wheel is then consolidated. This procedure offers aplurality of advantages. Thus, only a markedly lower number of verycost-intensive core molds have to be kept on hand within the frameworkof series production. Due to the lower necessary number of sealing linesat the consolidation mold compared to inserting the preform with thecore mold, this has a markedly simpler design and therefore is alsocost-effective. Not least, an uncoupling of the fiber deposition and theconsolidation can be achieved in this embodiment.

In an alternative embodiment of the process, the fiber preform with thecore mold is inserted into the consolidation mold. In this embodiment,an addition of a binder is advantageously not necessary during the fiberdeposition.

An RTM, Resin Transfer Molding, a mold made of plastic or preferablymade of metal materials, is preferably used in the process according tothe present invention. The matrix material is preferably injected viaone or more resin injection ports, which are preferably arranged inlumps, linearly or in a channel-shaped manner in the mold.

In a preferred embodiment of the process according to the presentinvention, the bending over and forming in one piece of the tube-shapedfiber material takes place on the axial limiting surface of the rim wellcore by means of the auxiliary core. In this case, this auxiliary core,after it was moved out of the tube-shaped fiber material depositedthereon in the axial direction, is again moved axially back in thedirection of the rim well core. By means of the axial limiting surfaceof the auxiliary core, the continuous fibers are consequently formed inone piece with the axial limiting surface of the rim well core. In thiscase, the axial limiting surfaces of the rim well core and auxiliarycore, which are directed toward each other, are preferably designed asideally shaped counterparts in order to thus advantageously makepossible an especially positive-locking and uniform fiber position withas few air pockets as possible. Likewise preferable is a special designof the radial limiting surface of the auxiliary core, as a result ofwhich a deposition of fiber material already adapted to the desiredgeometry of the wheel disk is advantageously carried out. With a solidauxiliary core, a reduction of the circumference is hence only possiblein the direction facing away from the rim well core, since, otherwise,the extraction of the auxiliary core from the fiber material cannot becarried out in this direction.

Also preferably, the auxiliary core is designed such that its volume canbe set in a variable manner. Consequently, a reduction of thecircumference of the auxiliary core is also possible in the directionfacing away from the rim well core. If an auxiliary core has such a formin the deposition of the fiber material, then its volume is suitablyreduced before the extraction from the tube-shaped fiber material. Suchan auxiliary core preferably has a conical contour tapering in thedirection facing away from the rim well core. As a result, less fibermaterial is advantageously deposited along this direction, whichadvantageously brings about a reduced formation of folds of the fibermaterial during the bending over and forming in one piece of the fibermaterial on the axial limiting surface of the rim well core. Inaddition, the radial limiting surface especially preferably has agradual reduction of the circumference in the direction facing away fromthe rim well core. This advantageously makes possible the especiallypositive-locking forming in one piece of the fibers with the axiallimiting surface of the rim well core, imaging a centering surface ofthe wheel disk. Such an auxiliary core is preferably inflatable forcontrollable change in its volume or designed as fillable with a fluidor designed as elastic and stabilizable.

Furthermore, the rim well core itself also preferably has a multipart,especially two-part design and especially consists of a first and asecond part. Here, the first part of the rim well core images theprofile of the rim well of the rim to be manufactured in the area of thewheel flange not connecting to the wheel disk and of the well. Thesecond part of the rim well core then images the profile of the rim wellin the undercut area of the wheel flange connecting to the wheel disk,i.e., especially from this wheel flange up to the beginning of the well.Both parts of the rim well core are here preferably designed aspositive-locking with one another and detachably connectable with oneanother. In particular, the second part of the rim well core can bepushed or pressed onto the first part of the rim well core in the formof a circular ring or can be mounted on same in the form of individualcircle segments. Especially preferably, the first part of the rim wellcore has, for this, a mounting surface, especially preferably fasteningmeans, for the second part of the rim well core and thus extends, like aone-part rim well core, over the entire width of the rim well of thewheel to be manufactured in the axial direction. In the area of themounting surface of the second part, the first part of the rim well coreespecially preferably has a similar circumference as in the area of thewell and/or an outer shape which is approximately cylindrical andunprofiled aside from fastening means for the second part of the rimwell core.

The multipart or two-part design of the rim well core consisting ofparts, which can be detachably connected with one another,advantageously guarantees, among other things, the removability of therim well core from the fiber preform in the process according to thepresent invention. Because of the one-part design of the wheel to bemanufactured, one side of the wheel is closed at least partly with thewheel disk. Thus, the rim well core can be removed only from theopposite side. However, this is made difficult or impossible in aone-part design of the rim well core through the undercut area of thewheel flange connecting to the wheel disk. On the other hand, in atwo-part design of the rim well core, the first part of the rim wellcore is first removed from the fiber preform in the axial direction.Consequently, the second part of the rim well core can be removed fromthe undercut area of the wheel flange in the radial direction and canthen be easily removed from the fiber preform in the axial direction.

To make the removability of the rim well core from the fiber preformpossible, further embodiments of a one-part or multipart rim well coreare preferred. This rim well core is preferably designed as segmented,whereby especially preferably the segments forming the second part ofthe rim well core can be sunk in the first part of the rim well core.Also preferred is an inflatable embodiment of the rim well core,especially of the second part in a two-part design, or the fillabilityof the core with a fluid. This also advantageously makes possible theremovability of the rim well core, in which after the deposition of thefiber material its volume is reduced. In addition, also preferred is arim well core, which is designed as elastic and stabilizable and, e.g.,consists of an elastic outer core, e.g., of elastic plastic, which isstabilized by sufficiently pushing in the first part of the rim wellcore for the deposition of fibers. Furthermore, the removability of therim well core can advantageously be made possible, when the second partof the rim well core is applied, especially in a material-relatedmanner, such that it remains as a lost core in the rim or can be shrunkor dissolved due to the action of a medium or heat.

In an especially preferred embodiment, the process according to thepresent invention is carried out at first only using a core mold,consisting of the auxiliary core and the first part of the rim wellcore. In this case, an auxiliary core, which approximately ends with thefirst part of the rim well core in the radial direction, especially atthe level of the well, is especially preferably used. Consequently, asalready described, the bending over and positive-locking forming in onepiece of the deposited fiber material with the axial limiting surface,imaging the profile of the wheel disk, of the first part of the rim wellcore. Then, the second part of the rim well core is fastened to thefirst part of the rim well core and the fiber layers deposited thereon,such that it ends with these on their axial outer limiting surface.Especially preferably, a circular ring, which is pushed onto the firstpart of the rim well core, is used as the second part of the rim wellcore. For this, the first part of the rim well core is preferablyslightly conical at its outer end, and the second part of the rim wellcore is designed as an ideally shaped counterpart, in order to makepossible the pushing on of the second part of the rim well core up to adefined point. Once the second part of the rim well core has beenattached, fiber material is again deposited on this rim well core aswell as on an auxiliary core according to the process according to thepresent invention. In this case, an auxiliary core, which ends in theradial direction with the second part of the core, especially at thelevel of the wheel flange connecting with the wheel disk, is preferablyused. This advantageously makes possible the bending over andpositive-locking forming in one piece of the deposited fiber materialwith the axial limiting surface, imaging the profile of the wheel disk,of the second part of the rim well core, as well as the fiber layersalready deposited on the first part of the core. After the deposition aswell as forming of the fiber layers, the first part of the rim well corecan be removed in the axial direction from the fiber preform withoutproblems, before this fiber preform is then consolidated in a multipartouter mold. The second part of the rim well core preferably remains as alost core in the rim or is dissolved due to the action of a medium, andthe material is then preferably let out via openings in the preformprovided for this. Thus, a cavity filled with the lost core or unfilledis advantageously formed in the area of the wheel flange connecting tothe wheel disk and of the rim well, which brings about an advantageousincrease in the strength of the rim in this area.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a view of the deposition of a first layer of fiber material ona multipart core mold, consisting of an inner rim well core and a firstcylindrical auxiliary core by means of a radial braiding machine;

FIG. 2 is a view of the axial extraction of the first cylindricalauxiliary core from the tube-shaped fiber material deposited thereon;

FIG. 3 is a view of the inner rim well core with a first layer of fibermaterial deposited thereon in a positive-locking manner and formed inone piece therewith, as well as the outer rim well core which is mountedon these fiber layers and the inner core;

FIG. 4 is a view of the deposition of a second layer of fiber materialon a multipart core mold, consisting of an inner and an outer rim wellcore as well as a second cylindrical auxiliary core by means of a radialbraiding machine;

FIG. 5 is a view of the axial extraction of the second cylindricalauxiliary core from the tube-shaped fiber material deposited thereon;

FIG. 6 is a view of the inner rim well core with a first layer of fibermaterial deposited thereon in a positive-locking manner and formed inone piece therewith, as well as the outer rim well core which is mountedon this fiber material and the inner core with a second layer of fibermaterial deposited thereon in a positive-locking manner and formed inone piece therewith;

FIG. 7 is a cross sectional view of a rim profile, comprising a rim welland a wheel disk, with a lost core located in the area of the outerwheel flange, enclosed by fiber material;

FIG. 8 is a view of the deposition of a first layer of fiber material ona multipart core mold, consisting of an inner and an outer rim well coreand a cylindrical auxiliary core by means of a radial braiding machine;

FIG. 9 is a view of the deposition of a second layer of fiber materialon a multipart core mold, consisting of an inner and an outer rim wellcore and a cylindrical auxiliary core by means of a radial braidingmachine;

FIG. 10 is a view of the axial extraction of the cylindrical auxiliarycore from the tube-shaped fiber material deposited thereon;

FIG. 11 is a view of the inner and outer rim well core with fibermaterial deposited thereon in a positive-locking manner and formed inone piece therewith;

FIG. 12 is a cross sectional view of a rim profile, comprising a rimwell and a wheel disk, with a lost core located in the area of the outerwheel flange;

FIG. 13 is a cross sectional view of a rim profile, comprising a rimwell and a wheel disk;

FIG. 14 is a view of layers of fiber material deposited in apositive-locking manner on a multipart core mold, consisting of an innerand an outer rim well core and a cylindrical auxiliary core;

FIG. 15 is a view of the inner and outer rim well core with a layer offiber material deposited thereon in a positive-locking manner and formedin one piece therewith;

FIG. 16 is a cross sectional view of a rim profile, comprising a rimwell and a flange;

FIG. 17 is a cross sectional view of a rim profile showing therotational axis, the wheel flanges, the rim well and the wheel disc withbolt holes;

FIG. 18 is a front view of the wheel with a schematic display area wherethe fibers in the wheel disc are oriented in an angle of 90° in relationto the axis of rotation are schematically shown;

FIG. 19 is a front view of the wheel with a schematic display area wherethe angles of the fibers in the wheel disc are schematically shown; and

FIG. 20 is a side view of the wheel with a schematic display area wherethe angles of the fibers are schematically shown.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the first exemplary embodiment shown in FIGS. 1, 2, 3, 4, 5, 6 and 7,the wheel disk (23) is formed by means of the braiding of cylindricalmold parts, which have different diameters and which are used asauxiliary cores (6 a, 6 b). For this, at first the auxiliary core (6 a)is mounted in the area of the well of the rim well core (4, 5). Afterthe braiding of the auxiliary core (6 a) with a radial braiding machine(1), this is removed in the direction of the rotation symmetry axis (8),and the fiber textile (7) thus formed is applied to the rim well core(4, 5) by means of draping. An inlay (9) in the form of a ring issubsequently mounted by means of positive-locking mounting onto thebraided rim well core (4, 5). The inlay (9) images the partial contourof the rim well (21) from the well up to the wheel flange (22). Afterthe mounting of the auxiliary core (6 b), which is additionally used forfixing the inlay (9), the rim well core (4, 5), the inlay (9) and theauxiliary core (6 b) are braided. After the braiding of the auxiliarycore (6 b), this is removed in the direction of the rotation symmetryaxis (8), and the tube-shaped fiber textile (7) thus formed is appliedto the inlay (9) and the rim well core (4, 5) by means of draping.Consequently, the inlay (9) is completely enclosed by the fiber textile(7). A multipart metallic outer mold is used in the area of the rim well(21) and wheel disk (23) for the pressing of the textile layers duringthe consolidation.

In another embodiment shown in FIGS. 8, 9, 10, 11, 12 and 13, the wheeldisk (23) is formed by braiding a cylindrical mold part, which is usedas the auxiliary core (6 b). For this, at first, an inlay (9) is mountedby means of positive-locking mounting on the rim well core (4, 5). Theinlay (9) images the partial contour of the rim well (21) from the wellup to the wheel flange (22) and is designed as a lost core in the formof a ring or for a removal from the mold after the consolidation frommetal ring segments (10). After the mounting of the auxiliary core (6b), which is additionally used for fixing the inlay (9) or the ringsegments (10), the textile preforming is carried out by means of thebraiding process on a radial braiding machine (1). After the braiding ofthe auxiliary core (6 b), this is removed in the direction of therotation symmetry axis (8), and the fiber textile (7) thus formed isapplied to the inlay (9) or to the ring segments (10) and the rim wellcore (5) by means of draping. A multipart metallic outer mold is used inthe area of the rim well (21) and the wheel disk (23) for the pressingof the textile layers during the consolidation. The inlay (9) remains inthe component (11) after the consolidation. On the other hand, the ringsegments (10) are removed from the mold after consolidation. For this,the rim well core (4, 5) is removed in the direction of the rotationsymmetry axis (8), whereupon the ring segments (10) are removed from themold in the radial direction. For the pressing of the textile layersduring the consolidation, a multipart metallic outer mold is used in thearea of the rim well (21) and the wheel disk (23).

In yet another embodiment shown in FIGS. 14, 15 and 16, a wheel diskprojection is formed for mounting a wheel spider (25) or a wheel disk(23) by means of the braiding of a cylindrical mold part, which is usedas the auxiliary core (6 c). Metallic ring segments (10) here image thepartial contour of the rim well from the well to the wheel flange. Afterthe mounting of the auxiliary core (6 c), which is additionally used forfixing the ring segments (10), the textile preforming is carried out bymeans of the braiding process on a radial braiding machine (1). Afterthe braiding of the auxiliary core (6 c), this is removed in thedirection of the rotation symmetry axis (8) and the fiber textile (7)thus formed is applied to the ring segments (10) by means of draping. Amultipart metallic outer mold is used in the area of the rim well (21)and the wheel disk (23) for the pressing of the textile layers duringthe consolidation. The ring segments (10) are removed from the moldafter the consolidation. For this, the rim well core (5) is removed inthe direction of the rotation symmetry axis (8), whereupon the ringsegments (10) are removed from the mold in the radial direction.

FIG. 17 is a cross sectional view of a rim profile showing therotational axis (8), the wheel flanges 22, the rim well 21 and the wheeldisc 23 with bolt holes 24.

FIG. 18 is a front view of the wheel with a schematic display area (27)where the fibers (28) in the wheel disc (23) are oriented in an angle of90° in relation to the axis of rotation (8) are schematically shown.Axis of rotation (8) of the wheel is tilted in the layer of the drawingfor better understanding. Also shown is the wheel spider (25).

FIG. 19 is a front view of the wheel with a schematic display area (30)where the angles of the fibers (31) in the wheel disc (23) areschematically shown. The angles are 45° and −45° in relation to the axisof rotation (8) of the wheel. Axis of rotation of the wheel is tilted inthe layer of the drawing for better understanding. Also shown is thewheel spider (25).

FIG. 20 is a side view of the wheel with a schematic display area (29)where the angles of the fibers (32) are schematically shown. In theshown area of the rim well the angles of the fibers are 45° and −45° inrelation to the axis of rotation (8) of the wheel. Also shown is thewheel disc (23).

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:
 1. A process for manufacture of a wheel made offiber composite, the process comprising the following process steps:providing two wheel flanges, a rim well arranged between said two wheelflanges and a wheel disk passing over into at least one of said wheelflanges; preparing a core mold, having a cylinder-like rim well core anda cylindrical auxiliary core connected in an axial direction anddetachably connected with the rim well core, whereby a shape of the rimwell core corresponds to a shape of the rim well, said wheel flanges andan outer area of the wheel disk, and the rim well core is shaped, suchthat said rim well core can be removed after consolidation of the wheel;depositing at least one layer of fiber material on the core mold, sothat a tube of fiber material lies on the core mold and the wheelflanges; removing the auxiliary core from the tube made of fibermaterial deposited thereon; bending over of the fiber material that ispreviously deposited on the auxiliary core, and applying said fibermaterial to a face of the rim well core; consolidating the fibermaterial with a matrix material in a consolidation mold; and removingthe wheel from the consolidation mold.
 2. A process in accordance withclaim 1, wherein: in depositing said at least one layer of fibermaterial on the core mold, a binder is additionally added to the fibermaterial during depositing said at least one layer of fiber material onthe core mold, and said binder is activated after depositing said fibersand pre-consolidates the fiber material; and the core mold is removedafter pre-consolidating the fiber material.
 3. A process in accordancewith claim 1, wherein: the fiber material is inserted with the core moldinto the consolidation mold; and the core mold is removed from the moldafter consolidating the fiber material.
 4. A process for the manufactureof a wheel made of fiber composite in accordance with claim 1, whereinthe rim well core has a segmented structure for guaranteeingremovability.
 5. A process in accordance with claim 1, wherein the rimwell core is one or more of designed as inflatable or fillable with afluid in an undercut area of the at least one of the wheel flanges;designed as elastic and stabilizable by means of an extractable, rigidinner ring in the undercut area of the at least one of the wheelflanges; and a two-part design, whereby one part of the rim well coreremains as a lost core in the wheel, or is removable.
 6. A process forthe manufacture of a wheel made of fiber composite in accordance withclaim 5, wherein a removable part of the rim well core can be shrunk ordissolved due to action of a medium or heat.
 7. A process for themanufacture of a wheel made of fiber composite in accordance with claim1, wherein the rim well core has a multipart design, whereby a firstpart of the rim well core images an area from a first wheel flange in adirection towards a rim center and a second, lost part, of the rim wellcore images a remaining area of the rim well, whereby in depositing saidat least one layer of fiber material on the core mold comprisesdeposition of fibers first taking place on the first part of the rimwell core and a contact surface of said rim well core to the second partof the rim well core, subsequently the second part of the rim well coreand the auxiliary core at the first part of the rim well core and saidsecond part of the rim well core is applied to the fiber materialapplied at said first part of the rim well core, and subsequently fibersare deposited on the second part of the rim well core and the auxiliarycore.
 8. A process for the manufacture of a wheel made of fibercomposite in accordance with claim 1, wherein fiber deposition takesplace as braiding, winding or a braiding process or by means ofdeposition of prepregs.
 9. A process for the manufacture of a wheel madeof fiber composite in accordance with claim 1, wherein continuous fibersof the fiber layer in an area of the rim well have a fiber angle of ±20°to ±75° in relation to an axis of rotation of the wheel.
 10. A processfor the manufacture of a wheel made of fiber composite in accordancewith claim 1, wherein continuous fibers of the fiber layer in an area ofthe rim well have a fiber angle of ±30° to ±70° in relation to an axisof rotation of the wheel.
 11. A process for manufacture of a wheel madeof fiber composite, the process comprising the following process steps:providing two wheel flanges; providing a rim well arranged between saidtwo wheel flanges; forming a wheel disk at least partly by means offiber layers, which extend, without interruption, from the rim well overthe at least one of the wheel flanges into the wheel disk.
 12. A processfor the manufacture of a wheel made of fiber composite in accordancewith claim 11, wherein said two wheel flanges, said rim wheel and saidwheel disk form a wheel structure, wherein a portion of each of saidfiber layers extends in a radial direction relative to a longitudinalaxis of said wheel structure and another portion of each of said fiberlayers extends parallel to said longitudinal axis.
 13. A process for themanufacture of a wheel made of fiber composite in accordance with claim11, wherein continuous fibers of the fiber layers in an area of the rimwell have a fiber angle of ±3° to ±87° in relation to an axis ofrotation of the wheel.
 14. A process for the manufacture of a wheel madeof fiber composite in accordance with claim 11, wherein continuousfibers of the fiber layers in an area of the wheel disk have a fiberangle of ±3° to ±87° in relation to a radial direction of the wheel. 15.A process for the manufacture of a wheel made of fiber composite inaccordance with claim 11, wherein continuous fibers of the fiber layersin an area of the rim well have a fiber angle of ±20° to ±75° inrelation to an axis of rotation of the wheel.
 16. A process for themanufacture of a wheel made of fiber composite in accordance with claim11, wherein continuous fibers of the fiber layers in an area of the rimwell have a fiber angle of ±30° to ±70° in relation to an axis ofrotation of the wheel.
 17. A process for the manufacture of a wheel madeof fiber composite in accordance with claim 11, wherein said fiberlayers are embedded in duro- or thermoplastic matrix material.
 18. Aprocess for manufacture of a wheel made of fiber composite, the processcomprising the following process steps: forming a wheel structure, saidwheel structure comprising a longitudinal axis, two wheel flanges, awheel disk and a rim well arranged between said two wheel flanges, atleast said wheel disk and said rim well comprising fiber layers, saidfiber layers extending continuously, without interruption, from said rimwell over at least one of said two wheel flanges to said wheel disk,wherein a portion of each of said fiber layers extends in a radialdirection relative to said longitudinal axis of said wheel structure andanother portion of each of said fiber layers extends parallel to saidlongitudinal axis.
 19. A process for the manufacture of a wheel made offiber composite in accordance with claim 18, wherein said fiber layersare embedded in duro- or thermoplastic matrix material, whereincontinuous fibers of the fiber layers in an area of the rim well have afiber angle of ±20° to ±75° in relation to an axis of rotation of thewheel structure.
 20. A process for the manufacture of a wheel made offiber composite in accordance with claim 18, wherein continuous fibersof the fiber layers in an area of the wheel disk have a fiber angle of±3° to ±87° in relation to a radial direction of the wheel structure.